Don Terrill’s Speed-Talk

SchmidtMotorWorks wrote: ↑Sun May 20, 2018 11:48 pm This CFD might be helpful to visualize.
The all receive the exact same signal.
Only one pulse is used and allowed to decay.

Scotthatch wrote: ↑Mon May 21, 2018 1:16 am

SchmidtMotorWorks wrote: ↑Sun May 20, 2018 11:48 pm This CFD might be helpful to visualize.
The all receive the exact same signal.
Only one pulse is used and allowed to decay.

So you agree with how that page works???

It says right on it that even the 2nd harmonic is only good for 10%

So ram is doing the other 90%

nitro2 wrote: ↑Tue Nov 15, 2011 1:35 pm Inertia = 0% Waves = 100%

Lets say we ignore the pulsing effects in the intake at IVO, for simplicity lets say they aren't there. Then at IVO, the inertia when the intake valve starts to open is 0. The inertia in the intake is going to stay at 0 indefinitely, unless acted upon. The action, piston motion (and also residual intake waves but we got rid of them above, and exhaust suction or reversion), causes wave action which in turn causes the intake motion and of course intake inertia increases. Same idea when its all slowing down, wave action happens then the intake motion decreases. Absolutely nothing happens in the intake without wave action, it just sits there stopped. The A/F mixture half way up the runner (or anywhere else) knows absolutely nothing about speeding up from dead stopped until a wave from the cylinder travels up the runner to tell it to get going, and it doesn't know to stop either until a wave tells it to stop. Actually its a series of waves not a simple sinusoidal wave (see further below).

It's important to understand that "wave tuning" as most people think of it is a very specific thing that is primarily related to what happens during overlap rather than during the rest of the cylinder filling period. Only during IVC to IVO do the events in the intake behave like a sinusoidal (or similar) wave and what this wave is doing just before overlap determines to a large degree what happens during overlap. The exhaust wave at overlap plays the other part. So how much effect so called "wave tuning" will have on power really depends largely on how much gain can be made by having a good overlap flush event vs. a not so good overlap flush event.

Wave tuning during the rest of the intake process (i.e. the main cylinder filling process) is a whole different story. The waves are simply an infinite series of tiny wave events all summed up. How they sum up determines what you get for cylinder filling. This is not a sinusoidal event at all. It is also the part of wave tuning that most people don't know too much about.

Scotthatch wrote: ↑Sun May 20, 2018 11:32 pm 15267463087920.jpg


So am I to assume that the people that posted fully agree with this page on acoustical wave and how it works to make power?

SchmidtMotorWorks wrote: ↑Sun May 20, 2018 11:48 pm This CFD might be helpful to visualize.
The all receive the exact same signal.
Only one pulse is used and allowed to decay.

DrillDawg wrote: ↑Mon May 21, 2018 11:03 am 1100 x 141 x .705 \ 6900 = 15.84

If your heads flowed 450 you would peak around 7500rpm, so....

1100 x 141 x .705 \ 7500 = 14.5"

that's why you see extended runners in some single plane intakes

That's using swampbuggy's 516 and 282 duration at .50

DrillDawg wrote: ↑Fri May 18, 2018 3:09 pm Intake tract length tuning

2nd pulse

((1100x 1\2intake can duration )x .96)\rpm

3rd pulse, same but use .705 instead of .96

4th pulse, Same but use .538 instead